Power transmission mechanism



Much 12, 1940. K. K. PROBST POWER TRANSMISSION MECHANISM Original FiledJune 18, 934 4 Sheets-Sheet 1 INVENTOR Karl Probsf w i L 2 I I A TTOR/VE1 5- March 12, .1940; K. K. PROBST ,193, 3

POWER TRANSMISSION MECHANISM Original Filed Jun 18, 1934 4 Sheets-Sheet2 INVENTOR ffar/ ff Pmbs/ 1 ATTORNEYS 4 Sheets-Sheet 3 Original FiledJune 18, 1934 WWW M v 1/ 11 mm- R W 1Kf4.

K. K. PROBST EOWER TRANSMISSION MECHANISM March 12,, 1940.

4 Sheets-Sheet 4 Original Filed June 18, 1934 11v VENTOR ff'ar/ K.Prabsf Wmze NE r5 BYZL Patented Mar. 12, 1940 UNITED STATES PATENTorFicE Application June 18, 1934, Serial No. 731,030. Renewed December8, 1937 4 Claims.

This invention relates to power transmission mechanism, and is moreparticularly directed to means for changing the driving ratio between aprime mover of a vehicle and the driving 6 wheels.

The invention embraces the provision of means for transmitting power tothe driving wheels of the vehicle, wherein simple and eflicient meansare utilized to change the driving wheels of the vehicle, especiallyadaptable for use when the vehicle has attained higher speeds tomaintain the vehicle speed at substantially reduced engine speed. 15 Theinvention comprehends a so-called overdrive power transmission wherein asuitable mechanism is associated with the main drive shaft and arrangedto be quickly and easily manipulated to render the overdrivetransmission eifective or ineffective.

The invention embraces an overdrive mechanism and particularly a systemof gearing and associated parts which are comparatively silent inoperation and of such character that the longitudinal thrusts underdriving stresses are substantially balanced through the angular relationof associated gears.

A further object of the invention is the provision of a simple andeffective gear clutching means associated with a synchronizing memberwhereby the manipulation of driving ratio change may be quickly andquietly obtained with a minimum of wear on the parts.

A further object of the invention resides in the provision of amechanism of this character adapted to be associated with the drivingaxle or differential of an automotive vehicle.

A still further object of the invention is the provision of a drive ofthis character having simple and efiective control means for changingthe driving ratio easily and effectively irrespective of the speed atwhich the mechanism is operating.

Further objects and advantages are within the scope of this inventionsuch as relate to the arrangement, operation and function of the relatedelements of the structure, to various details of construction and tocombinations of parts, elements per se, and to economics of manufactureand numerous other features as will be apparent from a consideration ofthe specification and drawings of a form of the invention, which may bepreferred, in which:

Figure l is a top plan view of a typical chassis ratio between the powerplant and the drive.

of an automotive vehicle showing a form of the invention incorporatedtherein;

Figure 2 is a sectional detailed view illustrating a form of overdrivemechanism of my invention;

Figure 3 is a detail sectional view taken substantially on the line 3-45of Figure 2;

Figure 4 is a vertical sectional detail View taken substantially on theline 4-4 of Figure 3;

Figure 5 is a fragmentary detailed view showing the arrangement ofadjusting certain elements of my invention.

Figure 6 is an enlarged fragmentary view illustrating the method andarrangement of adjustment of mechanism shown in Figure 5;

Figure 7 is a sectional detail view taken substantially on the line 1lof Figure 2;

Figure 8 is a diagrammatic illustration showing the degree ofadjustability and the directional factors afiecting the mechanism.

This invention is particularly adapted for use in connection with adriving mechanism of an automotive vehicle, especially those vehiclespowered by internal combustion wherein the power factors vary with thespeed of the engine for the purpose of establishing an over drive orchange in the ratio of speed between the prime mover or engine and thedrive wheels of the vehicle so that a comparatively high vehicle speeds,the engine speed may be reduced to a more eflicient operating speed yetmaintaining the vehicle speed. It is to be understood that thearrangement of the mechanism of the invention may be utilized in anypower transmitting mechanism where the same may be found to haveutility.

Referring to the drawings in detail and particularly Figure 1 thereof,an automotive vehicle chassis is illustrated, inclusive of a framestructure Ill, a forward axle or wheel support II, and a rear axle ormember enclosing driving mechanism, and I3 and M the associated sets ofvehicle wheels. The wheels M, in the embodiment illustrated, are thedriving wheels of the vehicle being suitably connected through themechanism contained in member i2 to a differential gear mechanismenclosed within a suitable housing IS. A prime mover or engine 20 whichmay be of the internal combustion type is mounted on or carried by theframe In and has a speed change transmission or gear set associatedtherewith positioned within a housing 22 preferably located amidship ofthe vehicle chassis.

Extending rearwardly from the transmission housing 22 is a stub shaft 2!and connectedthereto by means of a flexible coupling or universal jointarrangement 23 is a propeller or main drive shaft 25, which shaft isconnected by a second universal joint to the overdrive mechanism of myinvention positioned within a housing 2'! which is preferably mountedadjacent the differential housing it.

As illustrated in Figure 2, the housing It encloses a ring gear 3tmounted in driving relation with respect to the drive wheels through themedium of differential mechanism contained within casing 29 and driveaxles 3i and 32, or other suitable means.

In the arrangement of invention the propeller shaft 25 is connectedthrough a universal joint 25, one portion of the joint 26 being fixedlysecured to an extending spline portion 33 of a shaft 3 3, portion 25being held in place by means of a nut 35. The shaft 3d is journalled forrotation within the housing 2'! upon suitable anti-friction bearingssuch as the ball bearing arrangement 36 being held in place in thehousing by means of a snapring The portion of shaft 3 4 extending withinthe housing 2? is formed or provided with an enlarged portion 3? havingspaced clutch teeth 31' and a reduced extremity 33. The portion of shaft3G is preferably received within a hollow extension ti of a pinion shaft3i; formed with a driving pinion it, the shaft being suitably journalledfor rotation upon an anti-friction bearing 5 preferably of the balltype. Upon the end of pinion shaft 39 is suitably positioned a toothedclutch collar it keyed or otherwise secured to the shaft for rotationtherewith, and is held in place by an internally threaded ringengageable with the threaded portion 58 of the extension ii. Theanti-friction bearing M, preferably of the ball type, is positioned inthe housing 2'5 by means of a split ring 56 carried within an annulargroove 53 formed in anintegral web like portion 53' of the housing 2?.The teeth of pinion ii) are in constant mesh with the teeth of the ringgear 33 and the pinion is supported with respect thereto by means ofneedle bearing t? carried by a boss portion formed integral with thehousing El, the bearing engaging a reduced extension 43 of the pinionshaft 39.

In order to drive the pinion at the same speed as the main drive shaft35, I have provided a movable clutch member or collar iii) of annularconfiguration which is internally grooved or slotted for slidingengagement with the teeth on portion 3'? of the shaft 34 and the toothedcollar d5 mounted upon the pinion shaft 33. Thus, when the movableclutch element 55 is in the position illustrated in Figure 2, a drivingconnection is established between the shaft t l, pinion shaft 39, andthe pinion it formed thereon and the ring gear 39 is in direct drivingrelation with respect to the propeller or main drive shaft 25.

In order to maintain the speed of the ring gear 38 and thus the driveaxles 3! and 32 and at the same time reduce the engine speed, I haveprovided a second driving arrangement or overdrive. This arrangementincludes a gear having spiral or helical teeth journalled for rotationon shaft The gear 52 is in constant mesh with a gear 56 carried by asleeve or member mounted in parallel axial relation with respect to theshaft Sleeve 55 also carries at its other end a pinion gear 5'! adaptedfor constant enmeshment with the ring gear 30. The sleeve and gears 5dand 5? in the embodiment illustrated are of integral construction,however, the sleeve and gears may be separate units connected together.The sleeve 56 is suitably journalled upon an auxiliary shaft 58 andsupported directly upon anti-friction needle bearings 61 and 62 whichare separated by means of a bushing or collar 69.

By means such as washers or shims 66 at each end of the gears 54 and 57,the needle bearing elements are maintained in proper position withrespect to the sleeve 55, the shims also serving to properly positionthe sleeve and gears longitudinally. The gears 52 and 54 are preferablyof the helical spur tooth type to reduce gear noise to a minimum. Gear52 is provided with a radially toothed extension 59, the dogs or teethbeing adapted for slidable enmeshment with the splines or grooves in themovable clutch collar 56. By his arrangement, the clutch collar 59 maybe moved to the right, as viewed in Figure 2, and shaft 35 be connectedto and will drive the gear 52 and thus gear 5 and pinion 51. By suchdriving arrangement through the difference in ratio of the teeth ongears 52 and 54, it will be noted that the ring gear 38 will be drivenat a correspondingly higher speed while the shaft 34 is being driven ata comparatively low speed and by varying the sizes of the gears 52 and54, any desired ratio may be obtained. Further change in speed may beobtained by changing the size and number of teeth in the pinion 5'! andring gear 30.

Suitable means may be provided for shifting the clutch collar 50 and Ipreferably use a yoke member 62 engageable with a grooved portion 63 ofthe collar 56, the yoke 62 being secured to a longitudinally slidableoperating rod 65 as particularly illustrated in Figures 3 and 4. Theoperating rod 65 is preferably actuated by means of a lever 61 pivotallysupported by the housing 2? through a pivot or pin connection 58. To theother end of the lever 6'! is connected an operating means as forexample a flexible cable or wire H3. The operating Wire or cable 10 isenclosed by suitable shield or guiding sheath ll which is fixedlyconnected to a wall of the housing 21 and extends to a positionconvenient to the operator of the vehicle, such as the dashboard orinstrument panel, an operating button '58 or other suitable actuatingmeans being secured to the other end of wire 10.

Means are provided to insure either positive direct drive or positiveoverdrive and in the form illustrated this means is associated with theoperating rod 65. as at T2 and 73 to alternately receive the extremityof a spring pressed finger or pawl 14 mounted for sliding movementwithin a cup 16 carried by the cover plate 68.

The spring H is positioned between the pawl it and the bottom of the cupto urge the pawl into engagement with the rod 65. I have also provided agear synchronizing means facilitating the shifting of the clutch membercomprising a cup-shaped member 80 splined or otherwise secured to thepinion shaft 39, the open end of ,which is engageable with an. extendedportion 82 of the clutch collar 50 when the latter is shifted to theleft as illustrated in Figure 2. The member 80 is integrally formed witha plurality of resilient fingers 8i, and when the clutch collar 5% ismoved toward enmeshing position with the toothed member 45, theresilient fingers 8| first engage with clutch collar 50 and frictionallybring the collar and driving pinion 40 to sub- To this end the rod 65 isnotched stantially the same or synchronized speed prior to enmeshment ofthe clutch teeth so that smooth engagement is attained without toothclash. 'At the same time, the pawl it has begun its entrance into thenotch 13 and the pressure of spring ll aids in completing the engagementof the toothed clutches, and a positive driving connection is maintainedbetween the main drive shaft 3 1 and the pinion do until such time asthe operator of the vehicle shifts the clutch collar Bil into engagementwith the toothed clutch portion of the gear 52 to the overdrive gearinginto effective use. When the overdrive is being used the pawl Hi is inengagement with the notch 12 in the rod 65 and a driving connection isthus established between drive shaft 34, gear 512, and

through pinion 57 and ring gear to the drive axles.

In the arrangement of my invention I have substantially eliminatedlongitudinal thrusts which would ordinarily be transmitted to the membercarrying the overdrive gearing and this elimination of thrusts isaccomplished by utilizing h lical teeth upon gear 54 cut on an angleopposite to the angularity of the teeth upon the driving pinion 57 sothat under load there is substantially no tendency of the sleeve 56 tomove endwise. The tooth angles of the gear 54 and driving pinion 5? maynot bethe same due to the fact that the pinion is formed with spiralbevel teeth while the gear 5% is provided with helical spur teeth, butthe angles are preferably of such degree as to substantially oifsetendwise movement or thrusts when load is being transmitted through thisgearing. For example, I have found that a tooth havinga spiral angle forthe pinion construction 51 substantially balances the end thrusts whenused with a gear 5 having a helical angle of for the teeth thereof,although other combinations of gears having dilferent tooth angles willaccomplish substantially the same results.

The arrangement of my invention embodies a feature of adjustab litywhich I have found makes readily possible and practicable the commercialproduction in large quantities of the overdrive mechanism yet a highdegree of accuracy in manufacture of certain of the elements of thearrangement need not be maintained in order to insure a smooth runningand noiseless overdrive arrangement. To this end I have provided a meanswhereby the shaft or spindle 58 supporting the overdrive pinion 51 andspiral gear 56 is movable or adjustable laterally with respect to theaxis of the main. drive shaft so that the pinion 5'5 may be easily andquickly moved into proper enmeshment with the teeth of the ring gear 30.To this end, the enlarged extremities 9i and 9! of the auxiliary shaft.58 are eccentrically arranged with respect to an axis of theintermediate or main portion of the auxiliary shaft, this eccentricitybeing particularly exemplified in Figures 5 and 6 of the drawings. Theincluded angle between the lines a and b in Figures 5, 6 and 8represents the practical limits of lateral eccentric movement of theshaft 58 to secure the desired adjustability of the pinion with respect.to the ring gear as illustrated in Figure 7, the range of the actuallateral movement of the pinion being between points c and d asillustrated on Figures 5 and 8. The rotation of the eccentricallymounted shaft 53 in. the embodiment of my invention illustrated inFigures 5 and 6 is accompli hed by means of a sheet metal bracket 95having a tenon 95 the axis of the shaft 3? is indicated by dotted lines5 and 6, and the corresponding range of adjustment of the enmeshingteeth of th spur gear 5d and pinion 5! being indicated in dotted linesin Figures 5 and 7. It is to be noted that the axis of the auxiliaryshaft is above the center of the eccentric portions 86 and iii adistance The range of adjustment,

indicated at e in Figures 6 and 8, this dimension e being substantiallymidway between the central or uppermost position of the shaftas-indica'ted at f in Figure 8 and the lowermost extreme adjustedpositions 0 and d of center of the shaft. By this method of arrangingthe eccentricities of the tenons on the auxiliary shaftwith respect tothe principal axis of the shaft 5%, the lateral adjustment with respecttothe main. drive shaft which is. in the direction indicated by thearrow in Figure 8 is many times the corresponding degree of movement ofthe eccentrically mounted auxiliary shaft in a direction atsubstantially right angles to a plane passing through the axes of themain and auxiliary shafts.

Thus, by this system of adjustment, the lateral movement of the spurgear 54 and pinion 57 is suflicient to obtain a wide range of adjustmentto take care of any inaccuracies of manufacture, yet the verticalmovement of the axis of the spur gear and pinion is so small as to haveno appreciable effect upon the proper enmeshment of the gears. Moreover,this amount of vertical movement of the gears is not suficient inpractical application of the invention to cause the gears to becomenoisy in operation.

The auxiliary shaft 58 is provided with a speedometer driving gear l0!which is connected by suitable well known means to an odometer and speedindicating means of usual construction. By placing the speedometer gearon the auxiliary shaft the speedometer and odometer will registeraccurately the rate of speed and distances traveled as the inclusion ofthe overdrive gearing will not effect any change in ratio to thespeedometer operating mechanism.

It is apparent that, within the scope of the invention, modificationsand different arrangements may be made other than is herein disclosed,and the present disclosure is illustrative merely, the inventioncomprehending all variations thereof.

What I claim is:

1. Power transmission mechanism comprising a drive axle; a main driveshaft; a double toothed ring gear connected to said drive axle; a pinionmeshing with one set of teeth of said ring gear arranged in axialalignment with said main drive shaft; a spindle arranged substantiallyparallel to said main drive shaft, a sleeve journalled on said spindle;a helical gear journalled for rotation on said main shaft; a secondhelical gear associated with said sleeve and meshing with said firstmentioned helical gear; a second pinion associated with said sleeve andin mesh with another set of teeth on said ring gear; and means wherebydrive to said axle may be alternately established through either of saidpinions.

2. Power transmission mechanism comprising a drive axle; a main driveshaft; a double toothed ring gear connected to said drive axle; a pinionmeshing with one set of teeth of said ring gear arranged in axialalignment with said main drive shaft; a spindle arranged substantiallyparallel to said main drive shaft, a sleeve journalled on said spindle;a helical gear journalled for rotation on said main shaft; a secondhelical gear associated with said sleeve and meshing with said firstmentioned helical gear; a second pinion associated with said sleeve andin mesh with another set of teeth on said ring gear; means whereby driveto said axle may be alternately established through either of saidpinions; and means for shifting said spindle laterally with respect tosaid main drive shaft whereby the pinion associated with said sleeve maybe adjusted with respect to said ring gear.

3. A power transmission mechanism comprising a drive axle; a main driveshaft; a double toothed ring gear connected to said drive axle; a pinionmeshing with one set of teeth of said ring gear; a spindle arrangedsubstantially parallel to the axis of said pinion; a sleeve journalledon said spindle; helical gearing connecting said main drive shaft withsaid sleeve whereby the latter may be driven from the main drive shaft;

a second pinion associated with said sleeve and in mesh with another setof teeth on said ring gear; and means whereby a drive to said axle maybe alternately established through either of said pinions.

4. In combination, a vehicle drive axle; a double toothed ring gearconnected thereto; a main drive shaft; a spindle arranged insubstantially parallel relation to said main drive shaft; drivingpinions cooperatively associated with said main shaft and said spindleand in constant mesh with the teeth of said ring gear; a pair of helicaltoothed gears in constant mesh and carried respectively by said mainshaft and said spindle for changing the ratio of speed of said drivingpinions; means for selectively connecting said main shaft directly toone of said pinions or through said helical gearing to the other of saidpinions; and means for shifting said spindle laterally with respect tosaid main drive shaft whereby the pinion associated with said spindlemay be adjusted with respect to said ring gear, said spindle adjustingmeans including a key; a slot in said key; and means cooperating withsaid slot for retaining the spindle in adjusted position.

KARL K. PROBST.

